In extremes of passion, silly Celia gets the bird! (7)
I believe the answer is:
pelican
'the bird' is the definition.
(pelican is a kind of bird)
'in extremes of passion silly celia' is the wordplay.
'in' means one lot of letters goes inside another.
'extremes of' suggests removing the centre (only the letters at the extremes of the word).
'silly' indicates anagramming the letters.
'passion' with its middle taken out is 'pn'.
'celia' with letters rearranged gives 'elica'.
'pn' placed around 'elica' is 'PELICAN'.
'gets' acts as a link.
(Other definitions for pelican that I've seen before include "Its beak holds more than its belly can" , "Large-billed waterbird" , "one with huge bill" , "The large bird is in place" , "Nice pal (anag)" .)